1. Field
The present disclosure relates generally to fuel tanks and, in particular, to monitoring fuel tanks. Still more particularly, the present disclosure relates to a method and apparatus for measuring multiple parameters in a fuel tank.
2. Background
Identifying the amount of fuel present in a fuel tank is useful in operating aircraft. Information about the fuel level in the fuel tank may be displayed on a display in the cockpit of the aircraft. The information may be used by a pilot to determine how far the aircraft can fly. Additionally, this information may be used by computer systems in the aircraft to determine the range that the aircraft can fly with the present fuel level in the fuel tank.
A sensor is present in the fuel tank that provides information about the level of the fuel. This sensor may take various forms. For example, the sensor may be a float connected to a potentiometer, a capacitive probe, or some other suitable type of sensor.
With a capacitive probe, an outer tube may house an inner tube. Fuel fills an opening in the space between the outer and inner tubes. As the fuel level changes, the capacitance changes depending on the height of fuel in the tubes. This capacitance information indicates the amount of fuel present in the fuel tank.
The fuel level may be the height of the fuel in the fuel tank. The amount of fuel may be the number of gallons of fuel. This amount may be calculated from the fuel level detected in the fuel tank. The information about the fuel level is sent to a device outside of the fuel tank for display in the cockpit.
The device may be a controller that receives a signal from the capacitive probe through a wired connection. The controller may then provide output to the fuel gauge based on the signal received from the capacitive probe.
Further, it may be desirable to sense other parameters within the fuel tank other than fuel level. For example, one sensor system may be used to detect fuel level while another sensor system may be used to detect temperature.
With the use of different types of sensor systems, the complexity of components and wires used by the sensor systems may increase more than desired. As a result, the addition of these components may add more weight to the aircraft than desired. Moreover, the time needed to install or rework complex fuel tank sensor systems may be greater than desired.
Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.